I have two aftermarket 65W power supplies for an HP laptop, and the tip connector has failed on them.
The actual supply output is working fine, outputting the 20V DC, but the problem is the center pin, which no longer outputs the identifying voltage the laptop uses to determine the power capability of the supply.
I originally had only one bad but when I was trying to determine what failed on it and comparing it to the good one, I must have probed the center and shorted it to the +Vcc.
I saw about 9.1V on the center pin of the good one before, and about 3.4V on the bad when I probed it hot, so I think the configuration is a 165k resistor between the +Vcc to the center pin, and then a 9V Zener from the center pin to the return. That's the only thing that could explain how it went bad.
The tip is all encapsulated, so I'll have to try an archeological dig to try to find out how to replace the Zener to restore operation.
Are there any details on the center pin output so I can configure it correctly?
Is the 9V all that's required to have the laptop recognize the charger?
I may just use a simple divider to make it more fault tolerant if it's not too critical of the exact voltage, then there's no way I could blow it from errant probing. 165k to ground would do it, to get 10V.

 

Are you saying these are the 3-conductor sockets?

Helpful?
https://i.cubeupload.com/sBd5RH.gif

 

Yes, the input to connector from the power supply is two pin, and the output to the laptop is 3 conductors.
The center pin is the id pin.
I installed a 10V zener, but haven't tried it yet to see if it works.

 

The original failure was due to the center pin getting bent out of position and then the connector was forced in without knowing, causing it to contact the +20V on the inner barrel, destroying the regulation component.
Then in the course of trying to see what was inside the connector, I damaged a second one that was fine, until I probed it with a fat dmm probe with power on. Shorted the center to the power and poofed that one too.
This one I dug out to see what was in there. The blue pull-up resistor is visible from the dig out. I just clipped the lead to isolate the failed part and just attached the zener replacement.

 

Gawd I hate messing with these things. Good luck!

 

Gawd I hate messing with these things. Good luck!

Both of the tips worked after putting in the 9V zener diode, so it looks like that's all it needs.